Retarded Interfacial Formation of Polyamine-Based Nanofiltration Membranes with Pyromellitic Acid: Separation, Acid Stability, and Antifouling Performance

Crosslinked and additive-added polyamide thin-film composite(TFC)nanofiltration (NF) membranes formed by the conventional interfacialpolymerization (IP) process have shown good performances. However,studies on polyamine TFC NF membrane prepared via an adjusted IP processwith low-cost acid ligands as an interfacial additive for improvedliquid-based separation are still lagging. In this regard, a polyamine-basedTFC NF membrane synthesized by retarding the interfacial polymerization(IP) process with pyromellitic acid (PMA) (a polycarboxylate acidligand) is herein reported. The PMA-adjusted membrane displayed asuperb range of pure water fluxes from 9.8 to 20.4 L m(-2) h(-1) bar(-1), with the best-performedmembrane achieving up to 95.1% for Na2SO4 rejection.Thus, the water permeability of the PMA-TFC membrane is similar to 2.4times as high as the control TFC membrane. The best-performed PMA-TFCmembrane showed good hydrophilicity, pressure resistance, and long-termfiltration stability. In addition, the membrane structural stabilitywas maintained with similar to 3.9% declination in salt rejection after30 days of immersion in 0.1 M HNO3 solution. Also, an impressivefouling resistance was achieved after three-cycle of bovine serumalbumin fouling tests. This work, therefore, offers a more feasibleway of designing polyamine-based NF membranes with good prospectsin water reuse and nitric acid-generating wastewater treatment application.